Herbicidal cyanofluorophenoxyphenoxyalkanoic acids and derivatives thereof

ABSTRACT

Novel 2-(4-(2&#39;-fluoro-4&#39;-cyanophenoxy)-phenoxy)alkanoic acids and agriculturally acceptable derivatives thereof are selective postemergent herbicides for the control of grassy weeds in valuable crops. The novel herbicides are surprisingly selective, i.e., exhibit little or no phytotoxic effects, to wheat, barley and especially rice at concentrations that control undesired weed grasses.

RELATED U.S. APPLICATION DATA

Division of U.S. patent application Ser. No. 277,619, Nov. 29, 1988,U.S. Pat. No. 4,894,085, which is a continuation-in-part of U.S. patentapplication Ser. No. 82030, Aug. 5, 1987, abandoned.

BACKGROUND OF THE INVENTION

The present invention relates to novelcyanofluorophenoxyphenoxyalkanoates and derivatives thereof which areuseful as herbicides The present invention also relates to herbicidalcompositions containing these novel compounds and to the methods ofusing these compounds for the postemergent control of grassy weeds innon-crop areas, in broadleaf crops, as well as in the presence ofcertain valuable grass crops such as wheat, barley and especially rice.The invention is also directed to the novel stereoisomers of suchcompounds, the R-enantiomer having exceptional activity.

Various 2-(4-(cyano-and carbamylphenoxy)phenoxy)alkanoic acids andderivatives thereof are known as herbicidal agents For example, JapaneseKokai Tokkyo Koho 79 05,935 discloses various 2-(4-(cyano- andcarbamylphenoxy)phenoxy)alkanoic acids and derivatives thereof in whichthe cyano-and carbamylphenoxy group is further substituted withchlorine, bromine or iodine. British patent No. 1,545,001 discloses2-(4-(cyanophenoxy)phenoxy)alkanoic acids and certain derivativesthereof in which the cyanophenoxy group may be further substituted withhalogen, trifluoromethyl or cyano. The particularly preferredsubstituents are taught to be chlorine and trifluoromethyl. U.S. Pat.No. 4,550,192 discloses certain herbicidal 2-(4-(2'-fluoro-4'-halo-,haloalkyl-and haloalkoxyphenoxy)phenoxy acids and derivatives thereofbut does not disclose cyano substitution.

Heretofore, 2-(4-(2'-fluoro-4'-cyanophenoxy)phenoxy)alkanoic acids andagriculturally acceptable derivatives thereof have not been disclosed.

SUMMARY OF THE INVENTION

The present invention is directed to cyanofluorophenoxyphenoxyalkanoatesof the Formula (1): ##STR1## wherein R¹ represents a C₁ -C₃ alkyl group

and agriculturally acceptable derivatives, particularly the salts andesters of the alkanoic acid group thereof. The "*" denotes a chiralcarbon atom. Compounds with such chiral atoms can exist as enantiomers,i.e., mirror-image isomers that are not superimposable.

The compounds of the above Formula (I), hereinafter referred to as"active ingredients", have been found to be active as herbicides in thepresence of broadleaf crops and are unexpectedly superior in activitycompared to compounds known in the art. Furthermore, the compounds ofFormula (1) are surprisingly selective to certain cereal crops,especially rice, i.e., substantially non-phytotoxic to rice.Accordingly, the present invention also encompasses herbicidalcompositions containing one or more of the active ingredients as well asmethods of controlling unwanted vegetation. Such methods comprise, forexample, applying a herbicidally effective amount of one or more activeingredients postemergently to the locus of the undesired vegetation, andparticularly to the locus where a valuable crop is to germinate andgrow.

DETAILED DESCRIPTION OF THE INVENTION

The term "herbicide" is used herein to mean an active ingredient whichcontrols or adversely modifies the growth of plants By "growthcontrolling" or "herbicidally-effective" amount is meant an amount ofactive ingredient which causes an adversely modifying effect andincludes deviations from natural development, killing, regulation,desiccation, retardation and the like.

The term "plants", when used herein. is meant to include emergingseed-lings, rhizomes, stolons and other underground propagules, as wellas established The term "agriculturally acceptable derivatives", whenused to describe the active ingredients disclosed herein, is meant toencompass any salt amide, ester or other derivative of said activeingredients (acids) which

(1) does not substantially affect the herbicidal activity of said activeingredients, and

(2) is or can be hydrolyzed and/or oxidized in plants or soil to thealkanoic acid moiety of Formula (I) that, depending on the pH, is in thedissociated and/or undissociated form.

Agriculturally acceptable derivatives of the active ingredients, asdefined hereinabove, include but are not limited to compounds of Formula(II): ##STR2## Y represents a saturated or unsaturated alkyl groupcontaining an even number of carbon atoms, preferably from 2 to 6 carbonatoms;

n represents 0 or 1:

R¹ represents a C₁ -C₃ alkyl group; and

R² represents moieties corresponding to one of the following formulas:##STR3## wherein M represents a metallic cation, ammonium cation or anorganic amine cation, typically, but not exclusively, containing alkyl(saturated or unsaturated), alicyclic, heterocyclic or aromatic groups,all unsubstituted or substituted with various other groups not limitedto, but including, halo, cyano, nitro and unsubstituted or substitutedthiol hydroxy, amino or carboxyl groups and, additionally, alicyolic,heterocyclic and aromatic groups substituted with unsubstituted orsubstituted saturated or unsaturated alkyl groups, for example,trifluoromethyl, chloromethyl, cyanomethyl and vinyl; ##STR4## wherein Wrepresents --OR⁶, --SR⁶ or halogen;

A represents O or S;

R³ represents H or R⁶ ;

R⁴ represents H, alkoxy or R⁶ ;

R⁵ represents H, a metallic catio or R⁶ ; and

R⁶ represents an alkyl (saturated or unsaturated), alicyclic,heterocyclic or aromatic group, unsubstituted or substituted withvarious other groups not limited to, but including, halo, cyano, nitro,unsubstituted or substituted alkoxy, unsubstituted or substituted thiol,hydroxy, amino or carboxyl groups and, additionally, alicyclic,heterocyclic and aromatic groups substituted with unsubstituted orsubstituted saturated or unsaturated alkyl groups, for example,trifluoromethyl, chloromethyl, cyanomethyl and vinyl; ##STR5## wherein Bis O, S or N; or ##STR6## where R⁷ completes an unsubstituted orsubstituted heterocyclic ring system an A represents O or S.

In Formula (II) above, the aliphatic groups preferably contain 1 to 6carbon atoms, the alkenyl and alkynyl groups preferably contain 2-6carbon atoms, the alicyclic groups preferably contain 3 to 6 carbonatoms and the aromatic moiety is preferably phenyl, although other ringsystems. including heterocyclic ring systems, may be employed ifdesired.

R² is preferably a carboxylic acid group, an alkali or alkaline earthmetal salt thereof, an ammonium or organic amine salt thereof, an amideor lower alkyl amide thereof or a lower alkyl ester thereof, wherein"lower alkyl" includes straight, branched or cyclic saturated orunsaturated alkyl groups containing no more than 6 carbon atoms.Preferably, n is 0 and R¹ is methyl

The preferred compounds are of Formula (III) ##STR7## wherein R³ ishydrogen, a metallic cation, methyl, ethyl, propyl, iso-propyl, n-butyliso-butyl or sec-butyl The most preferred compounds are theR-enantiomers thereof.

The fluorophenoxyphenoxy compounds of Formula (II) above, also referredto as "active ingredients", can be prepared employing proceduresanalogous to wellknown procedures for preparing knownphenoxyphenoxyalkanoic acids and derivatives thereof U.S. Pat. Nos.4,550,192, 4,600,432 and British Patent No. 1,545,001 describe suchprocedures and are all incorporated herein by reference. For example,some of the compounds of Formula (II) can be prepared by reacting3,4-difluorobenzonitrile with an alkali or alkaline earth metal salt ofan appropriate (4-hydroxyphenoxy)alkanoic acid derivative in a suitablesolvent medium, such as dimethylsulfoxide (DMSO), dimethylformamide(DMF), N-methylpyrrolidone, hexamethylphosphoramide (HMPA) ortetrahydrofuran (THF). The reaction is advantageously carried out at atemperature from about 20° C. to about 150° C. This reaction can becharacterized as follows: ##STR8## wherein R¹, Y, n and R² are ashereinbefore defined This reaction is preferred for preparing compoundsof Formula (III). The metallic base is a base, such as, for example,NaOH, KOH, Na₂ CO₃ or K₂ CO₃.

Alternatively, some of the compounds of Formula (II) can be prepared byreacting an alkali or alkaline earth metal salt of4-(2'-fluoro-4'-cyanophenoxy)phenol with an appropriate alkanoatederivative containing a leaving group (Br, Cl or alkyl or arylsulfonate) in a suitable solvent medium, such as, DMSO, DMF, THF, HMPAor N-methylpyrrolidone. This reaction is advantageously carried out at atemperature of from about 20° C. to about 150° C. This reaction can becharacterized as follows: ##STR9## wherein R¹, Y, n and r² are ashereinbefore defined and L is Br, Cl or R⁸ SO₂ O where R⁸ is C₁ -C₄alkyl or unsubstituted or substituted phenyl. The metallic base is abase, such as, for example, NaOH, KOH, Na₂ CO₃ or K₂ CO₃.

The corresponding R-enantiomers may be prepared by using opticallyactive starting materials For example, the desired R-enantiomer may beprepared either by reacting 3,4-difluorobenzonitrile with theR-enantiomer of the (4-hydroxyphenoxy)alkanoic acid

derivative or by reacting the 4-(2'-fluoro-4'-cyanophenoxy)phenol withthe S-enantiomer of the appropriate alkanoate derivative, e.g., a2-halopropionate derivative. Alternatively, the R-enantiomers may beobtained from the racemate by conventional resolution procedures.

4-(2'-Fluoro-4'-cyanophenoxy)phenol and the alkali metal salts thereofare novel intermediate compounds and are within the scope of the presentinvention. These intermediates can be prepared by reacting3,4-difluorobenzonitrile with hydroquinone in a suitable solvent mediumsuch as, DMSO. DMF, THF, HMPA or N-methylpyrrolidone in the presence ofa metallic base. The reaction is advantageously carried out at atemperature from about 20° C. to about 150° C. and the metallic base isa base, such as, for example, NaOH, KOH, Na₂ CO₃ or K₂ CO₃. The reactioncan be characterized as follows: ##STR10## where M' is hydrogen, Na® orK®. Alternatively, these intermediates can be prepared by reacting3,4-difluorobenzonitrile with a stoichiometric amount of 4-methoxyphenolunder similar conditions The methyl ether of the resulting4-(2'-fluoro-4'-cyanophenoxy)methoxybenzene can be subsequently cleavedwith hydrobromic or hydroiodic acid in a suitable solvent medium, suchas, for example, acetic acid/acetic anhydride. The reaction isadvantageously carried out at a temperature from about 0° C. to about120° C. The reaction can be characterized as follows: ##STR11## Not allof the above derivatives of Formula (II) can be prepared directly by theprocesses described hereinabove because they may be susceptible totransformations under the reaction conditions employed Nevertheless,they can be made by conventional processes generally known to thoseskilled in the art and as described in U.S. Patent Nos. 4 ,565,568 and4,550,192 and in the references contained therein For example, thecorresponding acid chlorides can be reacted with alcohols or amines tomake the desired esters or amides; with a Grignard reagent to make thedesired ketone with KSH to make the desired thiol acid.

Once prepared, the compounds of the present invention are recoveredemploying standard well-known extraction and purification techniques,such as, for example, solvent extraction, crystallization orchromatographic separation.

The following examples illustrate the practice of the present inventionbut should not be construed as limiting its scope

Example 1 Preparation of methyl2-(4-(2'-fluoro-4-cyanophenoxy)phenoxy)propionate ##STR12##

(A) Methyl 2-(4-hydroxyphenoxy)propionate (5.88 grams (g); 0.03 moles)was dissolved in 50 milliliters (mL) of dimethyl sulfoxide (DMSO) and2.40 g of 50 percent NaOH (0.03 moles) was added. The mixture was warmedto 80° C. and 4.17 g (0.03 moles) of 3,4-difluorobenzonitrile (AldrichChemical Company) was added. The solution was heated and stirred at 80°C for 4 hours (hr). After cooling, the product was isolated byextraction with ethyl acetate. Unreacted phenolic starting material wasremoved by washing with dilute NaOH. Unreacted 3,4-difluorobenzonitrilewas removed from the concentrated extract utilizing a Kugelrohr. Theviscous oil that remained eventually crystallized on standing, m.p.57-58° C.

    ______________________________________                                        mass spectrum:   m/e 315                                                      infrared:        2280 cm.sup.-1 (CN)                                                            ##STR13##                                                   nuclear magnetic δ 1.65 (d, 3, CH.sub.3)                                resonance:       δ 3.75 (s, 3, OCH.sub.3)                                                δ 4.75 (q, 1, CH)                                                       δ 6.7-7.6 (m, 7, aromatic)                             ______________________________________                                    

Hydroquinone (5.5 g: 0.05 moles) was dissolved in 50 mL of dimethylsulfoxide and 8.0 g (0.1 moles) of 50 percent NaOH was added to thesolution The solution was heated and stirred at 80° C. and 7.0 g (0.05moles) of 3,4-difluorobenzonitrile in 10 ml of dimethyl sulfoxide wasadded dropwise. The reaction mixture was maintained at 80° C. for 2 hr.After cooling, the reaction mixture was poured into cold dilute HCl. Theprecipitate that formed was filtered and dried. The desired4-(2'-fluoro-4'-cyanophenoxy)phenol was purified by elution withchloroform from a silica gel column. The isolated product was obtainedas a white solid, m.p. 144-146° C.

    ______________________________________                                        mass spectrum:      m/e 229                                                   infrared:           3400 cm.sup.-1 (OH)                                                           2240 cm.sup.-1 (CN)                                       nuclear magnetic resonance:                                                                       δ(6-7, m, aromatic)                                 ______________________________________                                    

The 4-(2'-fluoro-4'-cyanophenoxy)phenol (2.29 g/0.01 moles) wasdissolved in 25 mL of dimethyl sulfoxide and 2.0 g of K₂ CO₃ was addedto the solution. The mixture was stirred and 2.46 g (0.011 moles) of thebenzenesulfonate of methyl lactate [₃ CH(OSO₂ C₆ H₅)CO₂ CH₃ ] was added.The reaction mixture was heated at 80° C. with stirring for 4 hr. Aftercooling, the product was isolated by extraction with benzene. Theinfrared and nuclear magnetic resonance spectra confirmed that theproduct was identical to that prepared in Example 1-A.

Example 2 Preparation of the R-enantiomer of methyl2-(4-(2'-fluoro-4'-cyanophenoxy)phenoxy) propionate

The R-enantiomer was prepared by substantially the same procedure asdescribed in Example 1-A except that anhydrous K2CO₃ was used as thebase and optically active R-methyl 2-(4-hydroxyphenoxy)propionate wasused as the starting material. The product was a solid with a m.p. of50° -53° C. An enantiomer ratio of 88.7 R/11.3 S was determined by HPLCusing a commercially available Chiracel OK column (cellulosetricinnamate: available from Daicel).

Example 3 Preparation of2-(4-(2'-fluoro-4'-cyanophenoxy)phenoxy)propionic acid

A solution of 1.5 g (4.8 mmoles) of methyl2-(4-(2,-fluoro-4'-cyanophenoxy)phenoxy)propionate and 0.4 g (6.1mmoles) of 85 percent KOH in 30 mL of methanol was stirred at roomtemperature for 24 hr. The methanol was evaporated under reducedpressure and the residue was dissolved in water. The solution wasacidified with 37 percent HCl to pH 2 and extracted with 100 ml ofether. The ether extract was dried over anhydrous MgSo₄, filtered andconcentrated under reduced pressure to a white solid. The solid wasrecrystallized from a 4:1 mixture of hot methylcyclohexane and tolueneto give 1.1 g of a fine white powder, m.p. 145-146° C.

    ______________________________________                                         Analysis         C         H      N                                          ______________________________________                                        Calculated for C.sub.16 H.sub.12 FNO.sub.4 :                                                    63.78     4.01   4.65                                       Found:            63.71     4.09   4.55                                       ______________________________________                                    

Example 4 Preparation of the R-enantiomer of2-(4-(2'-fluoro-4'-cyanophenoxy)phenoxy)propionic acid

The R-enantiomer was prepared by substantially the same procedure asdescribed in Example 3 except that the R-enantiomer of methyl2-(4-(2'-fluoro-4'-cyanophenoxy)phenoxy)propionic acid was used as thestarting material The product was a solid with a melting range of 115°-136° C. An enantiomer ratio of 88.5 R/11.5 S was determined by HPLC.

Example 5 Preparation of the sodium salt of the R-enantiomer of2-(4-(2'-fluoro-4'-cyanophenoxy)phenoxy)propionic acid

2-(4-(2'-Fluoro-4'-cyanophenoxy)phenoxy)propionic acid (1.60 g: 0.005mol) [R/S: 97/3]was dissolved in 50 mL of methanol and 50 percent NaOH(0.40 g; 0.005 mol) in 50 mL of methanol was added The methanol wasremoved under reduced pressure to give a white solid, m.p. 209-212° C.

    ______________________________________                                        infrared (Nujol):                                                                                ##STR14##                                                                    2255 cm.sup.-1 (CN)                                         nuclear magnetic  δ 1.35 (d, 3, CH.sub.3)                               resonance (DMSO-d.sub.6):                                                                       δ 4.30 (q, 1, CH)                                                       δ 6.75-8.20 (m, 7, aromatic)                          ______________________________________                                    

Example 6 Preparation of the ammonium salt of the R-enantiomer of2-(4-(2'fluoro-4'-cyanophenoxy)phenoxy)propionic acid

2-(4-(2'-fluoro-4'-cyanophenoxy)phenoxy)propionic acid (1.60 g; 0.005mol) [R/S: 97/3]was dissolved in methanol and saturated with anhydrousammonia at room temperature After evaporation of the solvent, theremaining solid was slurried in carbon tetrachloride-dichloromethane andfiltered, m.p. 155°- C. (decomp).

    ______________________________________                                        infrared (Nujol):                                                                                 ##STR15##                                                                    25555 cm.sup.-1 (CN)                                       nuclear magnetic   δ 1.35 (d, 3, CH.sub.3)                              resonance (DMSO-d.sub.6):                                                                        δ 4.30 (q, 1, CH)                                                       δ 6.70-8.20 (m, 11,                                                     aromatic & NH.sub.4)                                       ______________________________________                                    

Example 7 Preparation of the triethylammonium salt of the R-enantiomerof 2-(4-(2'-fluoro-4'-cyanophenoxy)phenoxy)propionic acid

2-(4-(2'-Fluoro-4'-cyanophenoxy)phenoxy)propionic acid (1.60 g 0.005mol) [R/S: 97/3] was dissolved in methanol and excess triethylamine wasadded to the solution. After evaporation of the solvent, the product wasisolated as a viscous oil.

    ______________________________________                                        nuclear magnetic                                                                                 ##STR16##                                                  resonance:        δ 1.40 (d, 3, CH.sub.3)                                                  ##STR17##                                                                    δ 4.60 (q, 1, CH)                                                       δ 6.65-7.95 (m, 7,                                                      aromatic)                                                   ______________________________________                                    

Example 8 Preparation of2-(4-(2'-fluoro-4'-cyanophenoxy)phenoxy)propionic acid

Powdered anhydrous K₂ CO₃ (48 g) was added to mL of dimethyl sulfoxideand 2-(4-hydroxyphenoxy)propionic acid was added to the dimethylsulfoxide slurry. The mixture was heated to 60° C. and stirred for 1 hr.3,4-Difluorobenzonitrile (20 g) was added to the mixture, thetemperature was increased to 85° C., and the mixture was stirred for anadditional 4 hr. After cooling, the salt was filtered and 20 mL of wateradded to the filtrate. The pH of the aqueous solution was adjusted to˜1.0 with dilute hydrochloric acid. The aqueous solution was extractedwith toluene (2X) and the combined organic extract washed with 100 mL of1.0 N HCl. The solvent was dried with MgSO4 and the solvent evaporatedto give crude acid. The crude acid was recrystallized from toluene togive product m.p. 45-146° C.

Example 9 Preparation of2-(4-(2'-fluoro-4'-cyanophenoxy)phenoxy)propionic acid chloride

2-(4-(2'-Fluoro-4'-cyanophenoxy)phenoxy)propionic acid (29.3 g: 0.097mol) was dissolved in 200 mL of toluene and 1 mL of dimethyl formamidewas added as a catalyst. Thionyl chloride (approx. 15 g) was added tothe stirred solution at room temperature and the solution was stirredfor 2 hr. The temperature was increased to 80-85° C. for approximately1.5 hr. After cooling and evaporation of volatiles on a rotaryevaporator, a viscous liquid was obtained which solidified on standing,m.p. 55-58° C.

    ______________________________________                                        infrared (Nujol):                                                                                ##STR18##                                                                    2200 cm.sup.-1 (CN)                                         nuclear magnetic  δ 1.80 (d, 3, CH.sub.3)                               resonance (CDCl.sub.3):                                                                         δ 5.00 (q, 1, CH)                                                       δ 6.80-7.70 (m, 7,                                                      aromatic)                                                   ______________________________________                                    

Example 10 Preparation of n-butyl2-(4-(2'-fluoro-4'-cyanophenoxy)phenoxy)propionate

2-(4-(2'-Fluoro-4'-cyanophenoxy)phenoxy)propionic acid chloride (3.19 g;0.01 mol) was dissolved in 25 mL of carbon tetrachloride. n-Butanol(0.74 g; 0.01 mol) and 1 mL of pyridine were dissolved in an equivalentamount of solvent The acid chloride solution was added dropwise to thealcohol-pyridine solution at room temperature over a 15 minute period.After stirring at room temperature for 1 hr, the product was isolated byextraction as a viscous oil. Gas-Chromatographic analysis indicated apurity in excess of 99 percent.

    ______________________________________                                        mass spectrum:   m/e 357                                                      infrared (Nujol):                                                                               ##STR19##                                                                    2250 cm.sup.-1 (CN)                                          nuclear magnetic                                                                                ##STR20##                                                   resonance (CDCl.sub.3):                                                                        δ 1.10-1.50 (m, 4,                                                       ##STR21##                                                                    δ 1.60 (d, 3, CH.sub.3)                                                 δ 4.20 (t, 2, OCH.sub.2)                                                δ 4.70 (q, 1, CH)                                                       δ 6.70-7.60 (m, 7, aromatic)                           ______________________________________                                    

Example 11 Preparation of (1-methylethyl)2-(4-(2'-fluoro-4'-cyanophenoxy)phenoxy)propionate

The procedure for Example 10 was repeated substituting an equivalentamount of iso-propyl alcohol for the n-butanol. The product was isolatedas a viscous oil whose purity exceeded 99% by gas chromatographicanalysis.

    ______________________________________                                        Calculated For:                                                                              C.sub.19 H.sub.18 FNO.sub.4                                                                  343                                             Found:         GC-MS          343                                             nuclear magnetic resonance (CDCl.sub.3):                                                      ##STR22##                                                     ______________________________________                                    

Example 12 Preparation of (1-methylpropyl)2-(4-(2'-fluoro-4'-cyanophenoxy)phenoxy)propionate

The procedure for Example 10 was repeated substituting an equivalentamount of sec-butyl alcohol for the n-butanol. The product was isolatedas a viscous oil whose purity exceeded 99% by gas chromatographicanalysis.

    ______________________________________                                        Calculated For:                                                                              C.sub.20 H.sub.20 FNO.sub.4                                                                  357                                             Found:         GC-MS          357                                             nuclear magnetic resonance (CDCl.sub.3):                                                      ##STR23##                                                     ______________________________________                                    

Example 13 Preparation of (2-methylpropyl)2-(4-(2'-fluoro-4'-cyanophenoxy)phenoxy)propionate

The procedure for Example 10 was repeated substituting an equivalentamount of iso-butyl alcohol for the n-butanol. The product was isolatedas a viscous oil whose purity by gas chromatographic analysis exceeded99%.

    ______________________________________                                        Calculated For:                                                                              C.sub.19 H.sub.18 FNO.sub.4                                                                  357                                             Found:         GC-MS          357                                             nuclear magnetic resonance (CDCl.sub.3):                                                      ##STR24##                                                     ______________________________________                                    

Example 14 Preparation of 2-(2-methoxypropyl)2-(4-(2'-fluoro-4'-cyanophenoxy)phenoxy)propionate

The procedure of Example 10 was repeated substituting an equivalentamount of 1-methoxy-2-propanol for the n-butanol. The product wasisolated as a viscous oil whose purity exceeded 99 percent bygas-chromatographic analysis.

    ______________________________________                                        mass spectrum: m/e 373                                                        ______________________________________                                        infrared (Nujol):                                                                       1750 cm.sup.-1                                                                             ##STR25##                                                        2250 cm.sup.-1                                                                            (CN)                                                    nuclear magnetic resonance (CDCl.sub.3):                                                         ##STR26##                                                  ______________________________________                                    

Example 15 Preparation of n-nonyl2-(4-(2'-fluoro-4'-cyanophenoxy)phenoxy)propionate

The procedure of Example 10 was repeated substituting an equivalentamount of n-nonyl alcohol for the n-butanol. The product was isolated asa viscous oil whose purity exceeded 99 percent by gas-chromatographicanalysis.

    ______________________________________                                        mass spectrum:        m/e 427                                                 infrared (Nujol):     1750 cm.sup.-1                                                                2250 cm.sup.-1                                          nuclear magnetic resonance (CDCl.sub.3):                                                            δ0.90 (t, 3 CH.sub.3)                                                   δ1.22 (s, 14, CH.sub.2)                                                 δ1.55 (d, 3, CH.sub.3)                                                  δ4.20 (t, 2, OCH.sub.2)                                                 δ4.75 (q, 1, CH)                                                        δ6.70-7.65 (m, 7,                                                       aromatic)                                               ______________________________________                                    

Example 16 Preparation of2-(4-(2'-fluoro-4'-cyanophenoxy)phenoxy)propionamide

2-(4-(2'-Fluoro-4'-cyanophenoxy)phenoxy)propionic acid chloride (approx.4g) was dissolved in 100 mL of toluene and the solution was sparged withanhydrous ammonia in excess. The product was isolated by filtration andwashing with water. After drying and recrystallization from acetone, theproduct had a m.p. 163-165° C.

    ______________________________________                                        mass spectrum: m/e 300                                                        ______________________________________                                        infrared   3400 cm.sup.-1                                                                            (NH.sub.2)                                             (Nujol):                                                                                 3200 cm.sup.-1                                                                            (NH.sub.2)                                                        2250 cm.sup.-1                                                                            (CN)                                                              1650 cm.sup.-1                                                                             ##STR27##                                             nuclear magnetic   δ1.45 (d, 3, CH.sub.3)                               resonance (DMSO-d.sub.6):                                                                        δ4.65 (q, 1, CH)                                                        δ6.80-8.15 (m, 9, aromatic                                              & NH.sub.2)                                                ______________________________________                                    

Example 17 Preparation of N-methyl2-(4-(2'-fluoro-4-cyanophenoxy)phenoxy)propionamide

The procedure of Example 16 was repeated substituting anhydrousmethylamine for the ammonia. The product, isolated by extraction andpurified by recrystallization from acetone-hexane, had a m.p. 118-120°C.

    ______________________________________                                        mass spectrum: m/e 314                                                        ______________________________________                                        infrared     3300 cm.sup.-1                                                                            (NH)                                                 (Nujol):                                                                                   2250 cm.sup.-1                                                                            (CN)                                                              1650 cm.sup.-1                                                                             ##STR28##                                           nuclear magnetic     δ1.40 (d, 3, CH.sub.3)                             resonance (DMSO-d.sub.6):                                                                          δ2.55 (d, 3, NCH.sub.3)                                                 δ4.65 (q, 1, CH)                                                        δ6.80-8.20 (m, 7,                                                       aromatic)                                                ______________________________________                                    

Example 18 Preparation of N,N-dimethyl2-(4-(2'-fluoro-4'-cyanophenoxy)phenoxy)propionamide

The procedure of Example 16 was repeated substituting anhydrousdimethylamine for the ammonia. The product, isolated by extraction andpurified by recrystallization from acetone-hexane, had a m.p. 93-95° C.

    ______________________________________                                        mass spectrum: m/e 328                                                        ______________________________________                                        infrared     2240 cm.sup.-1                                                                            (CN)                                                 (Nujol):                                                                                   1655 cm.sup.-1                                                                             ##STR29##                                           nuclear magnetic     δ1.45 (d, 3, CH.sub.3)                             resonance:                                                                                         δ3.00 (d, 6, N(CH.sub.3).sub.2)                                         δ5.25 (q, 1, CH)                                                        δ6.70-8.15 (m, 7,                                                       aromatic)                                                ______________________________________                                    

The compounds of the present invention, i.e., active ingredients, havebeen found to be suitable for use in methods for the postemergentcontrol of grasses, such as, barnyard grass, crabgrass, and Johnsongrass, in the presence of broadleaf crops, such as, cotton, soybeans andsugar beets. Further, it has been surprisingly found that the compoundsof Formula (I) above are selective, i.e., exhibit little or nophytotoxic effects, to wheat, barley and especially rice atconcentrations that control undesired weed grasses.

For all such uses, unmodified active ingredients of the presentinvention can be employed. However, the present invention embraces theuse of a herbicidally-effective amount of the active ingredients incomposition form with an inert material known in the art as anagricultural adjuvant or carrier in solid or liquid form. Such adjuvantsor carriers must not be phytotoxic to valuable crops particularly at theconcentration employed in applying the composition in attemptingselective weed control in the presence of crops. If weed control isdesired in the absence of crops, it is generally sufficient to employadjuvants or carriers which do not leave a persistent phytotoxicresidue.

Thus, for example, an active ingredient can be dispersed on afinely-divided solid and employed therein as a dust. Also, the activeingredients, as liquid concentrates or solid compositions comprising oneor more of the active ingredients can be dispersed in water, typicallywith aid of a wetting agent, and the resulting aqueous dispersionemployed as a spray. In other procedures the active ingredients can beemployed as a constituent of organic liquid compositions, oil-in-waterand water-in-oil emulsions or dispersions, with or without the additionof wetting, dispersing, or emulsifying agents

Suitable adjuvants of the foregoing type are well known to those skilledin the art The methods of applying the solid or liquid herbicidalformulations similarly are well known to the skilled artisan.

Organic solvents that can be employed include toluene, xylene, kerosene,diesel fuel, fuel oil, and petroleum naphtha, ketones such as acetone,methylethyl ketone and cyclohexanone, chlorinated hydrocarbons such astrichloroethylene, and perchloroethylene, esters such as ethyl acetate,amyl acetate and butyl acetate, ethers, e.g., ethylene glycol monomethylether and diethylene glycol monomethyl ether, alcohols, e.g., methanol,ethanol, isopropanol, amyl alcohol, ethylene glycol, propylene glycol,butylcarbitol acetate and glycerine Mixtures of water and organicsolvents, either as emulsions or solutions, can be employed

The active ingredients of the present invention can also be applied asaerosols, e.g. by dispersing them by means of a compressed gas such asone of the fluorocarbons or one of its hydrocarbon successors.

The active ingredients of the present invention can also be applied withsolid adjuvants or carriers such as talc, pyrophyllite, synthetic finesilica, attapulgus clay, kieselguhr, chalk, diatomaceous earth, lime,calcium carbonate. bentonite Fuller's earth, cotton seed hulls, wheatflour, soybean flour, pumice, tripoli, wood flour, walnut shell flour,redwood flour and lignin.

As stated, it is frequently desirable to incorporate a surface-activeagent in the compositions of the present invention. Such surface-activeor wetting agents are advantageously employed in both the solid andliquid compositions. The surface-active agent can be anionic, cationicor nonionic in character.

Typical classes of surface-active agents include alkyl sulfonate salts.alkylaryl sulfonate salts. alkylaryl polyether alcohols, fatty acidesters of polyhydric alcohols and the alkylene oxide addition productsof such esters, and addition products of long-chain mercaptans andalkylene oxides. Typical examples of such surface-active agents includethe sodium alkylbenzene sulfonates having 10 to 18 carbon atoms in thealkyl group, alkyl phenol ethylene oxide condensation products, e.g.,p-isooctylphenol condensed with 20 ethylene oxide units, soaps, e.g.,sodium stearate and potassium oleate, sodium salt of propylnaphthalenesulfonic acid, di(2-ethylhexyl)ester of sodium sulfosuccinic acid,sodium lauryl sulfate, sodium decyl sulfonate, sodium salt of thesulfonated monoglyceride of coconut fatty acids, sorbitan sesquioleate,lauryl trimethyl ammonium chloride, octadecyl trimethyl ammoniumchloride, polyethylene glycol lauryl ether, polyethylene glycol estersof fatty acids and rosin acids. e.g., Ethofat 7 and 13, sodiumN-methyl-N-oleyl taurate, sodium dibutylnaphthalene sulfonate, sodiumlignin sulfonate, polyethylene glycol stearate, sodium dodecyl benzenesulfonate, tertiary dodecyl polyethylene glycol thioether (nonionic218), long-chain ethylene oxidepropylene oxide and condensationproducts, e.g., Pluronic 61 (molecular weight about 1000), polyethyleneglycol ester of tall oil acids, sodium octophenoxyethoxyethyl sulfate,tris(polyoxyethylene)sorbitan monostearate (Tween 60), and sodiumdihexylsulfosuccinate.

The concentration of the active ingredients in solid or liquidcompositions generally is from about 0.003 to about 95 percent by weightor more. Concentrations from about 0.05 to about 50 percent by weightare often employed In compositions to be employed as concentrates, theactive ingredient can be present in a concentration from about 5 toabout 98 weight percent, preferably 15-50 weight percent The activeingredient compositions can also contain other compatible additaments,for example, phytotoxicants, plant growth regulants, pesticides and thelike and can be formulated with solid particulate fertilizer carrierssuch as ammonium nitrate, urea and the like

The present compositions can be applied by the use of powder dusters,boom and hand sprayers, spray dusters, granule applicators, by additionto irrigation water, by hand application as in the case of granules, andby other conventional means. The compositions can also be applied fromairplanes as a dust or spray since the active ingredients are effectiveat very low application rates.

In the following illustrative compositions, parts and percentages are byweight

Emulsifiable Concentrates

    ______________________________________                                        Formulation A                                                                                       WT %                                                    ______________________________________                                        R-enantiomer of methyl 2-(4-(2'-fluoro-                                                               26.2                                                  4'-cyanophenoxy)phenoxy)propionate                                            Polyglycol 26-3         5.2                                                   Nonionic emulsifier-(di-sec-butyl)-                                           phenyl-poly(oxypropylene)block polymer                                        with (oxyethylene). The polyoxyethylene                                       content is about 12 moles.                                                    Witconate P12-20 (Anionic emulsifier-                                                                 5.2                                                   calcium dodecylbenzene sulfonate-                                             60 wt. % active)                                                              Aromatic 100 (Xylene range aromatic                                                                   63.4                                                  solvent)                                                                      ______________________________________                                    

    ______________________________________                                                              WT %                                                    ______________________________________                                        Formulation B                                                                 R-enantiomer of methyl 2-(4-(2'-fluoro-                                                               3.46                                                  4'-cyanophenoxy)phenoxy)propionate                                            Sunspray 11N (paraffin oil)                                                                           40.00                                                 Polyglycol 26-2         19.00                                                 Oleic acid              1.00                                                  Xylene range aromatic solvent                                                                         36.54                                                 Formulation C                                                                 Methyl 2-(4-(2'-fluoro-4'-cyano-                                                                      13.2                                                  phenoxy)phenoxy)propionate                                                    Stepon C-65             25.7                                                  Ethomeen T/25           7.7                                                   Ethomeen T/15           18.0                                                  Xylene range aromatic solvent                                                                         35.4                                                  ______________________________________                                    

These concentrates can be diluted with water to give emulsions ofsuitable concentrations for controlling grassy weeds in cultivations ofplants.

Wettable Powders

    ______________________________________                                                              WT %                                                    ______________________________________                                        Formulation D                                                                 Methyl 2-(4-(2'-fluoro-4'-cyano-                                                                      25.99                                                 phenoxy)phenoxy)propionate                                                    Polyglycol 26-3         2.00                                                  Polyfon H               4.00                                                  Zeosyl 100 (Precipitated hydrated SiO.sub.2)                                                          17.00                                                 Barden clay + inerts    51.01                                                 Formulation E                                                                 Methyl 2-(4-(2'-fluoro-4'-cyano-                                                                      62.37                                                 phenoxy)phenoxy)propionate                                                    Polyfon H (sodium salt of lignin                                                                      6.00                                                  sulfonate)                                                                    Sellogen HR (sodium naphthalene                                                                       4.00                                                  sulfonate)                                                                    Zeosyl 100              27.63                                                 ______________________________________                                    

The active ingredient is applied to the corresponding carriers and thenthese are mixed and ground to yield wettable powders of excellentwettability and suspension power. By diluting these wettable powderswith water it is possible to obtain suspensions of suitableconcentrations for controlling grassy weeds in cultivations of plants.

Water Dispersible Granules

    ______________________________________                                        Formulation F                                                                                    WT %                                                       ______________________________________                                        Methyl 2-(4-(2'-fluoro-4'-cyano-                                                                   26.0                                                     phenoxy)phenoxy)propionate                                                    Sellogen HR          4.0                                                      Polyfon H            5.0                                                      Zeosyl 100           17.0                                                     Kaolinite clay       48.0                                                     ______________________________________                                    

The active ingredient is applied in a liquid state to the hydratedsilica which is then mixed with the other ingredients and ground to apowder The powder is agglomerated with water and sieved to providegranules in the range of -10 to +60 mesh. By dispersing these granulesin water it is possible to obtain suspensions of suitable concentrationsfor controlling grassy weeds in cultivations of plants

Granules

    ______________________________________                                        Formulation G                                                                                    WT %                                                       ______________________________________                                        Methyl 2-(4-(2'-fluoro-4'-cyano                                                                    5.0                                                      phenoxy)phenoxy)propionate                                                    Celetom MP-88        95.0                                                     ______________________________________                                    

The active ingredient is applied in a liquid state to the Celetom MP-88carrier or to other suitable carriers. The resulting granules can beapplied directly to paddy rice water by hand, granule applicator,airplane, etc. in order to control grassy weeds in rice.

    ______________________________________                                        Formulation H                                                                                    WT %                                                       ______________________________________                                        Methyl 2-(4-(2'-fluoro-4'-cyano                                                                    1.0                                                      phenoxy)phenoxy)propionate                                                    Polyfon H            8.0                                                      Nekal BA 77          2.0                                                      Zinc Stearate        2.0                                                      Barden Clay          87.0                                                     ______________________________________                                    

All materials are blended, ground to a powder, then water is added andthe clay mixture is stirred until a paste is formed. The mixture isextruded through a die to provide granules of proper size for directapplication to paddy water.

The active ingredients of the present invention have been found topossess desirable herbicidal activity in general against grassy weedssuch as foxtail, wild oats, barnyard grass and crabgrass in postemergentoperations The active ingredients possess desirable herbicidal activityagainst the grassy weeds, described above, while at the same time aretolerant or selective to broadleaf crops, such as, cotton and soybeans.The compounds of Formula (I) are surprisingly tolerant or selective towheat, barley and especially rice

The exact rate to be applied is dependent not only on a specific activeingredient being applied, but also on a particular action desired (e.g.,general or selective control), the plant species to be modified, and thestage of growth thereof as well as the part of the plant to be contactedwith the toxic active ingredient. Thus, it is to be understood that allof the active ingredients of the present invention and compositionscontaining the same may not be equally effective at similarconcentrations or against the same plant species.

In non-selective postemergent operations a dosage of about 0.001 toabout 20 kilograms/hectare or more is generally applicable, although notall compounds are equally effective and some weeds are more difficult tocontrol A dosage rate in the range of about 0.01 to about 1.0kilograms/hectare is preferred in selective postemergent control ofannual grassy weeds, while about 0.025 to about 5 kilograms/hectare ispreferred and more preferably about 0.05 to about 2 kilograms/hectarefor the selective postemergent control of perennial grassy weeds

In general, foliar treatments are preferred to soil treatments.

Example A Postemergent Activity

Representative compositions of the present invention were evaluated forthe postemergence control of species of plants listed in Table A. Inthese evaluations, plots of the plant species listed in Table A, grownto a height of about 4 inches, were used. Aqueous spray compositions,containing various amounts of2-(4-(2'-fluoro-4'-cyanophenoxy)phenoxy)propionic acid methyl ester, ie., 1000 ppm, 500 ppm, 250 ppm, 125 ppm, 62.5 ppm and 31.25 ppm,respectively, were applied to separate plots. The spray compositionswere made by mixing the active ingredient in acetone to 1/2 the finalvolume, i.e., twice the final concentration. An equal amount of aqueousspray solution was added to the active ingredient/acetone mixturewherein the aqueous spray solution contained 20 percent iso-propylalcohol, 2 percent crop oil concentrate and 0.04 percent Triton®X-155.The application to the plants was made to the point of runoff and wascarried out with a hand-held syringe. Other plots were sprayed withsimilar compositions containing no toxicant to serve as controls.Thereafter, the plots were maintained under conditions conducive forplant growth. Two weeks after treatment, the plots were examined forplant growth and evaluated on a scale of 0 to 100 where 0 represents noeffect and 100 represents complete kill. The results of the examinationof the treated plots are set forth below in Table A

®Trademark of Rohm and Haas Company

                  TABLE A                                                         ______________________________________                                        Percent Kill and Control of Plants at Various                                 Concentrations (ppm) of Methyl 2-(4-(2'-fluoro-                               4'-cyanophenoxy)phenoxy)propionate                                            Concentration (ppm)                                                           Plant  Control   1000   500   250  125  62.5 31.25                            ______________________________________                                        Rape   0         60     60     0    0    0   0                                Velvet 0         30     20    20    0    0   0                                leaf                                                                          Corn   0         80     80    80   70   70   70                               Rice   0          0      0     0    0    0   0                                Sorghum                                                                              0         80     80    70   70   70   40                               Wheat* 0          0      0     0    0    0   0                                Barn-  0         100    100   90   70   70   0                                yard                                                                          Grass                                                                         Crab-  0         80     70    30    0    0   0                                grass                                                                         Giant  0         100    80    70   60   60   20                               Foxtail                                                                       Johnson                                                                              0         100    100   90   40   60   0                                Grass                                                                         Wild   0         40     40    60   40   40   0                                Oats                                                                          Yellow 0         100    90    75   70   70   20                               Foxtail                                                                       ______________________________________                                         *in other tests slight phytotoxicity to wheat has been observed at the        high dose rates                                                          

At 1000 ppm and below, methyl2-(4-(2'-fluoro-4'-cyanophenoxy)phenoxy)propionate was also selective,i.e. no phytotoxic effect, to cotton, soybeans, sugar beets, jimsonweed,morning glory, pigweed cocklebur, lambsquarters, wild buckwheat.coffeeweed and yellow nutsedge.

By applying the well-accepted probit analysis as described by J. Berksonin Journal of the American Statistical Association, 48, 565 (1953) andby D. Finney in "Probit Analysis" Cambridge University Press (1952), theabove data can be used to calculate GR₅₀ and GR₈₀ values, which aredefined as growth reduction factors that correspond to the effeotivedose of herbicide required to kill or control 50 percent or 80 percent,respectively, of a target plant. From the above data, a GR₅₀ of about132 ppm and a GR₈₀ of about 546 ppm with respect to grassy weeds can becalculated.

Example B Postemergent Activity

Substantially the same procedures as those described in Example A wererepeated except that the active ingredient was the optically activeR-enantiomer of 2-(4-(2'-fluoro-4'-cyanophenoxy)phenoxy)propionic acidmethyl ester. The results are listed in Table B.

                  TABLE B                                                         ______________________________________                                        Percent Kill and Control of Plants at Various                                 Concentrations (ppm) of R-Methyl 2-(4-(2'-fluoro-                             4'-cyanophenoxy)phenoxy)propionate                                            Concentration (ppm)                                                           Plant  Control   1000   500   250  125  62.5 31.25                            ______________________________________                                        Rape   0         100    70    30    0    0    0                               Velvet 0          20    30    15    0    0    0                               leaf                                                                          Corn   0         100    80    80   70   70   65                               Rice   0          0      0     0    0    0    0                               Sorghum                                                                              0          80    80    70   70   70   50                               Wheat  0          45    20     0    0    0    0                               Barn-  0         100    100   90   85   80   65                               yard                                                                          Grass                                                                         Crab-  0          80    70    60   60   25    0                               grass                                                                         Giant  0         100    100   80   60   60   30                               Foxtail                                                                       Johnson                                                                              0         100    100   85   70   70   60                               Grass                                                                         Wild   0          80    70    70   40   40   20                               Oats                                                                          Yellow 0         100    100   85   80   70   60                               Foxtail                                                                       ______________________________________                                    

At 1000 ppm and below, R-methyl2-(4-(2'-fluoro-4'-cyanophenoxy)phenoxy)propionate was also selective tocotton, soybeans, sugar beets, jimsonweed, morning glory, coffeeweed,wild buckwheat, pigweed, cocklebur, lambsquarters and yellow nutsedge.

Against grassy weeds, GR₅₀ and GR₈₀ values of approximately 49 ppm and327 ppm respectively can be calculated from the above data.

Example C Postemergent Activity Dryland Rice

The rice plants and weeds were grown in a clay loam soil. The plantswere treated at the indicated leaf (lf) stage. Treatments were appliedon a grams/hectare basis through a tracksprayer at an application volumeof 187 liters/hectare. The R-enantiomer of methyl2-(4-(2'-fluoro-4'-cyanophenoxy)phenoxy)propionate (90.5 percentR-configuration), as a 26.2 percent emulsifiable concentrate, was mixedwith predetermined amounts of aqueous solution containing 0.25 percentnon-ionic surfactant X-77* and applied at seven rates of activeingredient as a serial dilution. Evaluations were made two weeks aftertreatment with 0 representing no visible effect and 100 representingcomplete kill. The results are listed in Table C.

                                      TABLE C                                     __________________________________________________________________________    Percent Kill and Control of Grassy Weeds at Various Concentrations            (g/ha)                                                                        of R-Methyl 2-(4-(2'-fluoro-4'-cyanophenoxy)phenoxy)propionate                         Growth                                                                        Stage at                                                                            Concentration (grams/hectare)                                  Plant    Treatment                                                                           Control                                                                            400                                                                              200                                                                              100                                                                              50                                                                              25                                                                              12.5                                                                             6.3                                       __________________________________________________________________________    Rice     2  lf 0     0  0  0  0                                                                               0                                                                               0 0                                         Sprangletop                                                                            3  lf 0    100                                                                              85 70 20                                                                              20                                                                               5 5                                         Barnyard Grass                                                                         2-3                                                                              lf 0    90 80 70 20                                                                               0                                                                               0 0                                         Jungle Rice                                                                            2-3                                                                              lf 0    99 88 95 70                                                                              45                                                                              43 0                                         Smooth Crabgrass                                                                       2-3                                                                              lf 0    93 80 75 60                                                                              10                                                                              10 0                                         Johnson Grass                                                                          2-3                                                                              lf 0    78 55 15  0                                                                               0                                                                               0 0                                         Fall Panicum                                                                           1-2                                                                              lf 0    98 90 95 93                                                                              95                                                                              75 23                                        Texas Panicum                                                                          1-2                                                                              lf 0    95 85 75 63                                                                              75                                                                               0 0                                         Yellow Foxtail                                                                         1-2                                                                              lf 0    93 80 88 53                                                                              20                                                                              13 0                                         Green Foxtail                                                                          2-3                                                                              lf 0    100                                                                              78 63 10                                                                               0                                                                               0 0                                         Bermuda Grass                                                                          1-2                                                                              lf 0    88 73 80 73                                                                              45                                                                              50 0                                         Goose Grass                                                                            2-3                                                                              lf 0    100                                                                              99 95 90                                                                              78                                                                              75 35                                        Broadleaf                                                                              2-3                                                                              lf 0    95 78 88 83                                                                              55                                                                              50 25                                        Signalgrass                                                                   Dallis Grass                                                                           2  lf 0    28 25 10  0                                                                               0                                                                               0 0                                         __________________________________________________________________________

Example D Postemergent Activity Paddy Rice-Water Injection Application

Rice plants, barnyard grass and sprangletop were grown in soil in 5 cmdiameter pots until plants reached the proper growth stage for treatment(1 to 3 weeks depending on species). The plants were then transplantedin 10 cm diameter cottage cheese containers and sandy soil was added tothe containers The containers were flooded to approximately 2.5 cm depthof water and the plants were allowed to acclimate for 24 hr prior totreatment. At the time of treatment, water level was adjusted as neededso weeds were partially immersed in water but rice was still exposed.Methyl 2-(4-(2'-fluoro-4'-cyanophenoxy)phenoxy)propionate was dissolvedin a predetermined amount of acetone and applied with a needle syringeinto the paddy water as a grams/hectare rate. Five rates were applied ata serial dilution. Evaluations were made 2 weeks after treatment with 0representing no visible effect and 100 representing complete kill. Theresults are listed in Table D.

                  TABLE D                                                         ______________________________________                                        Percent Kill and Control of Echinochloa crus-galli                            (Barnyard Grass) and of Leptochloa filiformis                                 (Sprangletop) at Various Concentrations                                       (grams/hectare) of Methyl 2-(4-(2'-fluoro-4'-                                 cyanophenoxy)phenoxy)propionate in Paddy Rice                                        Concentration (g/ha)                                                   Plant    Control  560      280  140   70  35                                  ______________________________________                                        Rice     0         0        0    0     0  0                                   Barn-    0        100      90   80    80  0                                   yard                                                                          Grass                                                                         Sprangle-                                                                              0        100      70   50    25  25                                  top                                                                            GR.sub.50  76 g/ha                                                                           Barn-                                                                         yard    GR.sub.80  305 g/ha                                                                         Sprangletop                             GR.sub.80  148 g/ha                                                                           Grass                                                         ______________________________________                                    

Example E Postemergent Activity Paddy Rice

Rice plants, barnyard grass and sprangletop were grown in soil in 5 cmdiameter pots until plants reached the proper growth stage for treatment(1 to 3 weeks depending on species). The plants were then transplantedinto 10 cm cottage cheese containers and sandy soil was added to thecontainers. The containers were flooded to approximately 2.5 cm depth ofwater and the plants were allowed to acclimate for 24 hr prior totreatment. At the time of treatment, the water level was lowered asneeded so the plant leaves were exposed. A 26.2 percent emulsifiableconcentrate of the R-enantiomer of methyl2-(4-(2'-fluoro-4'-cyanophenoxy)phenoxy)propionate (90.5 percentR-configuration) was mixed with water and 1 percent crop oil concentrateand applied with a hand syringe (spray nozzle) at predeterminedconcentrations of active ingredient. Five concentrations were sprayed asa serial dilution. Evaluations were made 2 weeks after treatment with 0representing no visible effect and 100 representing complete kill. Theresults are listed in Table E.

                  TABLE E                                                         ______________________________________                                        Percent Kill and Control of Echinochloa crus-galli                            (Barnyard Grass) and of Leptochloa filiformis                                 (Sprangletop) at Various Concentrations (ppm) of                              R-Methyl 2-(4-(2'-fluoro-4'-                                                  cyanophenoxy)phenoxy)propionate in Paddy Rice                                        Concentration (ppm)                                                    Plant    Control  250      125  62     31  16                                 ______________________________________                                        Rice     0         0        0    0      0   0                                 Barn-    0        87       85   55     35  17                                 yard                                                                          Grass                                                                         Sprangle-                                                                              0        100      100  100    97  90                                 top                                                                           ______________________________________                                    

Example F Postemergent Activity

Substantially the same procedures as those described in Example A wererepeated except that the active ingredient was the optically activeR-enantiomer of 2-(4-(2'-fluoro-4'-cyanophenoxy)phenoxy)propionic acid.The results are listed in Table F.

                  TABLE F                                                         ______________________________________                                        Percent Kill and Control of Plants at Various                                 Concentrations (ppm) of R-2-(4-(2'-fluoro-4'-                                 cyanophenoxy)phenoxy)propionic acid                                           Concentration (ppm)                                                           Plant  Control   250    125   62.5 31.25                                                                              15.62                                                                              7.8                              ______________________________________                                        Corn   0         90     90    80   70   40   0                                Rice   0          0      0     0    0   0    0                                Sorghum                                                                              0         100    80    80   70   0    0                                Wheat  0         15      0     0    0   0    0                                Barn-  0         90     80    80   65   0    0                                yard                                                                          Grass                                                                         Crab-  0         90     90    80   25   0    0                                grass                                                                         Giant  0         90     90    80   75   60   0                                Foxtail                                                                       Johnson                                                                              0         100    80    70   70   20   60                               Grass                                                                         Wild   0         80     70    30    0   0    0                                Oats                                                                          Yellow 0         100    90    90   80   0    0                                Foxtail                                                                       ______________________________________                                    

At 250 ppm and below,R-2-(4-(2'-fluoro-4'-cyanophenoxy)phenoxy)propionic acid was selective,i.e., no phytotoxic effect to cotton, soybeans, rape, sugar beets,coffeeweed, cocklebur, jimsonweed, lambsquarter, morning glory, pigweed,velvetleaf, wild buckwheat and yellow nutsedge.

Example G Postemergent Activity Paddy Rice-Water Injection Applications

Substantially the same procedures as those described in Example D wererepeated except that the active ingredient was2-(4-(2'-fluoro-4'-cyanophenoxy)phenoxy)propionic acid. The results arelisted in Table G.

                  TABLE G                                                         ______________________________________                                        Percent Kill and Control of Echinochloa crus-galli                            (Barnyard Grass) and of Leptochloa filiformis                                 (Sprangletop) at Various Concentrations                                       (grams/hectare) of 2-(4-(2'-fluoro-4'-                                        cyanophenoxy)phenoxy)propionic in Paddy Rice                                         Concentration (g/ha)                                                   Plant    Control  560     280  140    70   35                                 ______________________________________                                        Rice     0        10       0   0      0    0                                  Barn-    0        90      65   0      0    0                                  yard                                                                          Grass                                                                         Sprangle-                                                                              0        100     80   60     10   0                                  top                                                                           ______________________________________                                    

Example H Postemergent Activity Wheat and Barley Crops

Substantially the same procedures as those described in Example C wereutilized except that the active ingredient, methyl2-(4-(2'-fluoro-4'-cyanophenoxy)phenoxy)propionate, was formulated as anaqueous spray composition. This spray composition was prepared as inExample A. The results are listed in Table H.

                  TABLE H                                                         ______________________________________                                        Percent Kill and Control of Grassy Weeds at Various                           Concentrations (grams/hectare) of Methyl 2-(4-(2'-                            fluoro-4'-cyanophenoxy)phenoxy)propionate                                     Concentration (g/ha)                                                          Plant   Control    1000   250   63  15   4   1                                ______________________________________                                        Wheat   0           0      0     0   0    0   0                               Barley  0           3      0     0   0    0   0                               Rice    0           0      0     0   0    0   0                               Barn-   0          99     99    98  88   43  27                               yard                                                                          Grass                                                                         Crab-   0          93     90    90  80   67  22                               grass                                                                         Yellow  0          83     87    78  47   48  37                               Foxtail                                                                       ______________________________________                                    

Example I Postemergent Activity Paddy Rice-Water Injection Application

Substantially the same procedures as those described in Example D wererepeated. The tests were conducted on rice plants and sprangletop. Thesodium, ammonium and triethylammonium salts of the R-enantiomers of2-(4-(2'-fluoro-4-'-cyanophenoxy)phenoxy)propionic acid, the η-butyl,2-(`-methoxypropyl) and η-nonyl esters of racemic2-(4-(2'-fluoro-4'-cyanophenoxy)phenoxy)propionic acid, and theunsubstituted, N-methyl and N,N-dimethyl amides of racemic2-(4-(2'-fluoro-4'-cyanophenoxy)phenoxy)propionamide were included inthe evaluation. The results are summarized in Table I.

                  TABLE I                                                         ______________________________________                                        Percent Kill and Control of Leptochloa filiformis                             (Sprangletop) at Various Concentrations of                                     ##STR30##                                                                    in Paddy Rice                                                                          Concentration (g/ha)                                                                      Con-                  GR.sub.50                          Z          Plant     trol   200  100  50   (g/ha)                             ______________________________________                                        ONa(R)     rice      0      0    0    0                                                  sprangletop                                                                             0      98   70   17   76                                 ONH.sub.4 (R)                                                                            rice      0      10   0    0                                                  sprangletop                                                                             0      100  70   7    81                                 ONHEt.sub.3 (R)                                                                          rice      0      0    0    0                                                  sprangletop                                                                             0      97   63   0    95                                 On-Bu(R,S) rice      0      10   0    0                                                  sprangletop                                                                             0      80   13   0    143                                 ##STR31## rice sprangletop                                                                        0 0    10 100                                                                             0 58 0 0   97                                On-Nonyl (R,S)                                                                           rice      0      0    0    0                                                  sprangletop                                                                             0      92   57   0    101                                NH.sub.2 (R,S)                                                                           rice      0      10   0    0                                                  sprangletop                                                                             0      97   58   0    97                                 ______________________________________                                    

The N-methyl and N,N-dimethyl amides were not active below 200 g/ha inthis test.

Example J Postemergent Activity

Substantially the same procedures as those described in Example A wererepeated. A somewhat different spectrum of grassy plants were employed.The treatments were applied on a parts per million (ppm) basis. One partper million approximately corresponds to 2.6 g/ha.

The sodium, ammonium and triethylammonium salts of the R-enantiomers of2-(4-(2'-fluoro-4'-cyanophenoxy)phenoxy)propionic acid, the η-butyl,2-(1-methoxypropyl) and η-nonyl esters of racemic2-(4-(2'-fluoro-4'-cyanophenoxy)phenoxy)propionic acid, and theunsubstituted, N-methyl and N,N-dimethyl amides of racemic2-(4-(2'-fluoro-4'-cyanophenoxy)phenoxy)propionamide were included inthe evaluation. The results are summarized in Table J.

                                      TABLE J                                     __________________________________________________________________________    Percent Kill and Control of Grassy Weeds at                                   Various Concentrations (ppm) of                                                ##STR32##                                                                                        Concentration (ppm)                                       Z       Plant  Control                                                                            1000                                                                             500                                                                              250                                                                              125                                                                              62.5                                                                             31.25                                                                            15.62                                                                            7.81                                 __________________________________________________________________________    ONa(R)  rice   0    -- -- -- -- -- -- -- --                                           wheat  0    -- -- -- -- -- -- -- --                                           corn   0    -- -- 95 95 85 40 20 0                                            sorghum                                                                              0    -- -- 75 75 65 60 40 25                                           barnyard                                                                             0    -- -- 75 85 65 50 25 0                                            grass                                                                         crabgrass                                                                            0    -- -- 75 75 70 60 30 0                                            giant foxtail                                                                        0    -- -- 75 75 70 60 50 0                                            Johnson grass                                                                        0    -- -- 70 70 60 50 0  0                                            wild oat                                                                             0    -- -- 80 80 60 30 0  0                                            yellow foxtail                                                                       0    -- -- 60 60 50 40 0  0                                                   GR.sub.50 54 ppm                                               ONH.sub.4 (R)                                                                         rice   0    -- -- 0  0  0  0  0  0                                            wheat  0    -- -- 0  0  0  0  0  0                                            corn   0    -- -- 100                                                                              90 60 20 0  0                                            sorghum                                                                              0    -- -- 75 75 50 40 20 20                                           barnyard                                                                             0    -- -- 80 80 50 40 40 0                                            grass                                                                         crabgrass                                                                            0    -- -- 70 75 70 70 20 0                                            giant foxtail                                                                        0    -- -- 70 70 60 60 0  0                                            Johnson grass                                                                        0    -- -- 70 70 60 60 50 30                                           wild oat                                                                             0    -- -- 60 60 60 40 0  0                                            yellow foxtail                                                                       0    -- -- 80 75 65 25 0  0                                                   GR.sub.50 55 ppm                                               ONHEt.sub.3 (R)                                                                       rice   0    -- -- 0  0  0  0  0  0                                            wheat  0    -- -- 20 0  0  0  0  0                                            corn   0    -- -- 95 85 60 40 0  0                                            sorghum                                                                              0    -- -- 75 70 40 30 20 0                                            barnyard                                                                             0    -- -- 80 70 70 60 20 20                                           grass                                                                         crabgrass                                                                            0    -- -- 80 70 65 50 20 0                                            giant foxtail                                                                        0    -- -- 80 70 70 70 50 0                                            Johnson grass                                                                        0    -- -- 80 80 70 70 40 20                                           wild oat                                                                             0    -- -- 80 75 75 40 0  0                                            yellow foxtail                                                                       0    -- -- 60 50 50 20 20 0                                                   GR.sub.50 47 ppm                                               O.sub.nBu (R,S)                                                                       rice   0    -- -- 0  0  0  0  0  0                                            wheat  0    -- -- 20 0  0  0  0  0                                            corn   0    -- -- 90 65 40 40 0  0                                            sorghum                                                                              0    -- -- 70 75 50 30 30 20                                           barnyard                                                                             0    -- -- 90 75 50 30 20 0                                            grass                                                                         crabgrass                                                                            0    -- -- 50 40 40 0  0  0                                            giant foxtail                                                                        0    -- -- 70 70 70 50 25 25                                           Johnson grass                                                                        0    -- -- 70 70 65 50 25 25                                           wild oat                                                                             0    -- -- 70 70 50 20 0  0                                            yellow foxtail                                                                       0    -- -- 70 50 30 20 0  0                                                   GR.sub.50 80 ppm                                                ##STR33##                                                                            rice   0    -- -- 0  0  0  0  0  0                                            wheat  0    -- -- 0  0  0  0  0  0                                            corn   0    -- -- 90 90 90 60 20 0                                            sorghum                                                                              0    -- -- 65 50 50 40 20 20                                           barnyard                                                                             0    -- -- 70 70 65 40 40 25                                           grass                                                                         crabgrass                                                                            0    -- -- 70 70 70 30 0  0                                            giant foxtail                                                                        0    -- -- 75 70 70 60 0  0                                            Johnson grass                                                                        0    -- -- 75 70 70 60 30 30                                           wild oat                                                                             0    -- -- 75 50 0  0  0  0                                            yellow foxtail                                                                       0    -- -- 70 60 60 30 0  0                                                   GR.sub.50 67.5 ppm                                             O-n-Nonyl                                                                             rice   0    -- -- 0  0  0  0  0  0                                    (R,S)                                                                                 wheat  0    -- -- 20 0  0  0  0  0                                            corn   0    -- -- 95 70 60 50 0  0                                            sorghum                                                                              0    -- -- 60 50 70 30 20 20                                           barnyard                                                                             0    -- -- 75 75 70 55 30 20                                           grass                                                                         crabgrass                                                                            0    -- -- 70 70 70 20 0  0                                            giant foxtail                                                                        0    -- -- 75 70 60 50 20 0                                            Johnson grass                                                                        0    -- -- 65 65 50 50 25 20                                           wild oat                                                                             0    -- -- 60 60 50 0  0  0                                            yellow foxtail                                                                       0    -- -- 60 50 50 25 0  0                                                   GR.sub.50 72 ppm                                               NH.sub.2 (R,S)                                                                        rice   0    0  0  0  0  0  0  -- --                                           wheat  0    0  0  0  0  0  0  -- --                                           corn   0    25 20 0  0  0  0  -- --                                           sorghum                                                                              0    80 75 75 70 50 40 -- --                                           barnyard                                                                             0    60 50 50 30 0  0  -- --                                           grass                                                                         crabgrass                                                                            0    70 70 60 55 0  0  -- --                                           giant foxtail                                                                        0    70 70 60 50 35 0  -- --                                           Johnson grass                                                                        0    65 65 65 50 50 40 -- --                                           wild oat                                                                             0    60 60 40 0  0  0  -- --                                           yellow foxtail                                                                       0    70 70 60 50 0  0  -- --                                                  GR.sub.50 291 ppm                                              NHCH.sub.3 (R,S)                                                                      rice   0    0  0  0  0  0  0  -- --                                           wheat  0    0  0  0  0  0  0  -- --                                           corn   0    20 0  0  0  0  0  -- --                                           sorghum                                                                              0    70 60 60 60 0  0  -- --                                           barnyard                                                                             0    20 0  0  0  0  0  -- --                                           grass                                                                         crabgrass                                                                            0    10 0  0  0  0  0  -- --                                           giant foxtail                                                                        0    55 40 0  0  0  0  -- --                                           Johnson grass                                                                        0    50 45 50 35 0  0  -- --                                           wild oat                                                                             0    0  0  0  0  0  0  -- --                                           yellow foxtail                                                                       0    35 25 20 0  0  0  -- --                                   N(CH.sub.3).sub.2 (R,S)                                                               rice   0    0  0  0  0  0  0  -- --                                           wheat  0    0  0  0  0  0  0  -- --                                           corn   0    10 0  0  0  0  0  -- --                                           sorghum                                                                              0    50 40 20 0  0  0  -- --                                           barnyard                                                                             0    0  0  0  0  0  0  -- --                                           grass                                                                         crabgrass                                                                            0    30 10 0  0  0  0  -- --                                           giant foxtail                                                                        0    25 0  0  0  0  0  -- --                                           Johnson grass                                                                        0    30 20 0  0  0  0  -- --                                           wild oat                                                                             0    0  0  0  0  0  0  -- --                                           yellow foxtail                                                                       0    0  0  0  0  0  0  -- --                                   __________________________________________________________________________

Example K Postemergent Activity Dryland Rice

Substantially the same procedures as those described in Example C wererepeated. The tests were conducted on rice plants, barnyard grass andsprangletop. The methyl, iso-propyl, sec-butyl and iso-butyl esters ofracemic 2-(4-(2'-fluoro-4'-cyanophenoxy)phenoxy)propionic acid wereincluded in the evaluation. The results are summarized in Table K.

                                      TABLE K                                     __________________________________________________________________________    Percent Kill and Control of Echinochloa crus-galli                            (Barnyard Grass) and of Leptochloa filiformis                                 (Sprangletop) at Various Concentrations of                                     ##STR34##                                                                    in Dryland Rice                                                               Concentration (g/ha)                                                                                           GR.sub.80                                    Z      Plant   Control                                                                            400                                                                              200                                                                              100                                                                              50                                                                              25                                                                              (g/ha)                                       __________________________________________________________________________    OMe    rice    0     0  0  0  0                                                                               0                                                                              >400                                                barnyard grass                                                                        0    98 75 73 60                                                                              65                                                                              135                                                 sprangletop                                                                           0    100                                                                              98 95 78                                                                              40                                                                               63                                          O-iso-Pr                                                                             rice    0     0  0  0  0                                                                               0                                                                              >400                                                barnyard grass                                                                        0    95 70 73 60                                                                              55                                                                              155                                                 sprangletop                                                                           0    95 93 80 60                                                                              30                                                                              100                                          O-iso-Bu                                                                             rice    0     0  0  0  0                                                                               0                                                                              >400                                                barnyard grass                                                                        0    88 88 75 63                                                                              45                                                                              148                                                 sprangletop                                                                           0    93 75 60 40                                                                              20                                                                              206                                          O-sec-Bu                                                                             rice    0     0  0  0  0                                                                               0                                                                              >400                                                barnyard grass                                                                        0    90 75 73 70                                                                              68                                                                              165                                                 sprangletop                                                                           0    99 85 60 60                                                                              20                                                                              157                                          __________________________________________________________________________

The compounds of the present invention contain an optically activecenter as shown in Formula III (2-position of the propionic acid) andcan exist in optically active stereoisomeric forms. The R-enantiomersare distinguished by enhanced herbicidal activity. Both the pureenantiomers and various mixtures thereof are within the scope of thepresent invention.

In further embodiments, the compounds of the present invention orcompositions containing the same, can be advantageously employed incombination with one or more additional pesticidal compounds. Suchadditional pesticidal compounds may be insecticides, nematicides,arthropodicides, herbicides, fungicides or bactericides that arecompatible with the compounds of the present invention in the mediumselected for application and not antagonistic to the activity of thepresent compounds. Accordingly, in such embodiments, the pesticidalcompound is employed as a supplemental toxicant for the same or for adifferent pesticidal use, or as an additament. The compounds incombination can generally be present in the ratio of from 1 to 100 partsof the compound of the present invention with from 100 to 1 parts of theadditional compound(s).

For the purpose of lowering the labor for application or of increasingthe spectrum of effectively removable weed species, it is sometimespreferable to provide mixtures of the active ingredients with othercomplementary herbicides. Complementary herbicides that can be mixedwith the active ingredients include but are not limited to the followingcompounds:

Methyl2-((((((4,6-dimethoxypyrimidin-2-yl)amino)carbonyl)amino)sulfonyl)methyl)benzoate

3-Isopropyl-1H-2,1,3-benzothiadiazin-4(3H)one-2,2-ioxide (bentazon)

Ethyl5-[3-(4,6-dimethoxypyrimidin-2-yl)ureidosulfonyl]-1-methylpyrazole-4-carboxylate(NC-311

2-(3,5-Dichlorophenyl)-2-(2,2,2-trichloroethyl)oxirane (tridiphane)

4-Amino-3,5-dichloro-6-fluoro-2-pyridinyloxyacetic acid (fluoroxypyr)

3,5,6-Trichloro-2-pyridinyloxyacetic acid (triclopyr)

Methyl2-[4-((3-chloro-5-(trifluoromethyl)-2-pyridinyl)oxy)phenoxy]propionate(haloxyfop)

N-(3,4-dichlorophenyl)propanamide (propanil)

The active ingredients of Formula (II) can be hydrolyzed and/or oxidizedin the plants or soil to a carboxyl moiety that, depending on the pH, isin the undissociated and/or dissociated form. For example, an ester--COOR³ or an amide --CONR³ R⁴ can be hydrolyzed in the soil or theplant to the acid --COOH, which, depending on the pH, is in theundissociated --COOH form, the dissociated --COO⊖ form or an equilibriummixture of both forms Similarly, a valeric acid --CH(CH₃)CH₂ CH₂ COOH,for example, can be oxidized by microbial or plant metabolic β-oxidationto the corresponding propionic acid --CH(CH₃)COOH. In the most preferredembodiment of this invention, it is the propionic acid of Formula (III)that is the actual toxaphore in the grassy weeds This can be generallyestablished by studies in which the carboxylic acid in its undissociatedand/or dissociated form or as a derivative thereof is the most prevalentspecies detected within the plant. Since the agriculturally acceptablederivatives of Formula (II) are subject to such processes, the presentinvention contemplates a method of killing and/or controlling the growthof undesired grassy plants which comprises providing in said plants aherbicidally effective amount of a compound in the acid or salt formhaving the formula ##STR35## wherein R¹ is C₁ -C₃ alkyl.

Various modifications may be made in the present invention withoutdeparting from the spirit or the scope thereof and it is understood thatwe limit ourselves only as defined in the appended claims.

What is claimed is:
 1. The compound 4-(2'-fluoro-4'-cyanophenoxy)phenoland the alkali metal salts thereof.